Often, a user desires both the text processing functions of a text processor and access to a host data processor for data processing through a low cost data link. One solution to this problem is to utilize both a conventional text processor and a data display or printer compatible with the data processor. Such displays or printers are well known, e.g., the IBM 3278 Display Station and the IBM 3287 Printer, respectively. These devices essentially receive link data from the data processor and output it directly to the user. Another more desirable solution is to utilize the display or printer associated with the text processor as an output terminal for the host data processor. A system of this type has been described in copending U.S. patent application Ser. No. 310,184, filed Oct. 9, 1981, to Clements et al, now U.S. Pat. No. 4,458,311. In this application, an interactive system is provided which has the capability of switching from a text processing session to a data processing session wherein the text processor emulates a control unit and associated input/output terminals. While utilization of a text processor as a display and/or printer for a host data processor has produced satisfactory results, such a combination does not allow the user to process the formatted data before it is displayed on the display terminal. This is because the text processor cannot support the protocol normally associated with a control unit in a host data processor configuration. Moreover, this approach does not allow simultaneous yet independent use by the host data processor of both the display and printer associated with the text processor. Also, this approach is not functionally costeffective.
Therefore, there is a need for a terminal for use in an integrated text and data processing system which allows a user to process link data before output, and which provides simultaneous yet independent emulation of both the display and printer normally associated with the host data processor.